Cleanup compendium et monnaies

module/misc.js

@@ -47,6 +47,17 @@ export class Misc {
     return itemsBy;
   }
 
+  static classifyFirst(items, classifier) {
+    let itemsBy = {};
+    for (const item of items) {
+      const classification = classifier(item);
+      if (!itemsBy[classification]) {
+        itemsBy[classification] = item;
+      }
+    }
+    return itemsBy;
+  }
+
   static classifyInto(itemsBy, items, classifier = it => it.type, transform = it => it) {
     for (const item of items) {
       const classification = classifier(item);